Multi-ply linerboard machine with vertical and horizontal forming runs

ABSTRACT

A mechanism for making a multi-ply sheet such as a linerboard from fibrous stock including first and second looped forming wires extending to form a throat in a vertical upwardly extending forming run with the second wire wrapped over a suction couch roll and leading to a breast roll and a third looped wire wrapped over the breast roll and a headbox for discharging slurry over the first layer to be dewatered through the third wire with the moisture in the first layer being controlled by a suction couch roll. The multi-layered web is taken off of the second wire onto the third by a suction roll and transferred onto a felt to be led through a press nip.

United States Patent [1 1 Gustafson MULTI-PLY LINERBOARD MACHINE WITH VERTICAL AND HORIZONTAL FORMING RUNS [75] Inventor: David R. Gustafson, Rockton, I11.

[73] Assignee: Beloit Corporation, Beloit, Wis.

[22] Filed: Sept. 27, 1973 [21] Appl. No.: 401,170

[52] U.S. Cl. 162/299; 162/300; 162/303; 162/304; 162/305; 162/306 [51] Int. Cl. D2lf 1/00 [58] Field of Search 162/300, 298, 299, 301, 162/303, 203, 123, 133, 304, 305, 358, 306,

[56] References Cited UNITED STATES PATENTS 12/1956 Soderlund [62/306 X 2,881,670 4/1959 Thomas 162/299 X 3,471,367 10/1969 Chupka 162/123 X FOREIGN PATENTS OR APPLICATIONS 820,610 9/1959 United Kingdom 162/300 OTHER PUBLICATIONS Evans et al., Significant Trends in Paper Machine 11] 3,884,756 [451 May 20, 1975 Design and Operation-1, in Paper Trade Journal, August 9, 1971, pp. 30-35.

Pulp and Paper Making Notes, Scott Paper Company, First Edition, 1956 (p. 214).

Primary Examiner-S. Leon Bashore Assistant ExaminerRichard V. Fisher Attorney, Agent, or Firm-Hill, Gross, Simpson, Van Santen, Steadman, Chiara & Simpson [5 7] ABSTRACT A mechanism for making a multi-ply sheet such as a Iinerboard from fibrous stock including first and second looped forming wires extending to form a throat in a vertical upwardly extending forming run with the second wire wrapped over a suction couch roll and leading to a breast roll and a third looped wire wrapped over the breast roll and a he'adbox for discharging slurry over the first layer to be dewatered through the third wire with the moisture in the first layer being controlled by a suction couch roll. The multi-layered web is taken off of the second wire onto the third by a suction roll and transferred onto a felt to be led through a press nip.

13 Claims, 1 Drawing Figure MULTI-PLY LINERBOARD MACHINE WITH VERTICAL AND HORIZONTAL FORMING RUNS BACKGROUND OF THE INVENTION The invention relates to improvements in paper making machines and more particularly to improvements in a forming section of a paper making machine for making multi-ply web such as linerboard.

In linerboard machines heretofore available, at high operating speeds, difficulties were encountered in that adhesion or binding between the layers of the sheet became uncertain making the web unsatisfactory in certain circumstances and reducing its strength. Difficulty was also encountered in obtaining adequate drainage from both layers of the sheet, and particularly the second layer which preferably had to be drained outwardly of the first layer. Difficulty was also encountered in controlling the moisture of the first layer, and it has been discovered that it is very important for good ply bond between the top liner and bottom ply to control the moisture in the top liner.

It is a feature of the present invention to make linerboard by first making the bottom ply and thereafter forming the top liner on the surface of the bottom ply. The bottom ply is formed by controlling its moisture, and the top liner is applied thereafter. With the control of the moisture in the bottom ply to a degree that a sufficient amount of moisture is left in the bottom ply, a good ply bond can be obtained between the top liner and bottom ply. The amount of stock needed for the top liner is not very large, and the mechanism herein disclosed provides adequate drainage capacity to drain the water out of the top liner ply in its own direction after it has been laid on top of the bottom ply. The bottom ply is formed in a vertical forming run between two wires with the wires thereafter being separated and the second wire led through a horizontal run carrying the bottom ply. The top liner ply is formed by stock being delivered onto the surface of the lower ply, and the top liner ply is dewatered by running the two plies over the arcuate surface of a breast roll while applying a third wire to the outer surface. The breast roll may have a soft rubber cover, and the tension of the third wire' forces the water out of the web as the webs and wire wrap around the breast roll, and savealls are positioned to receive the water. The third wire has large voids to permit a large amount of water to be carried in the fabric itself, preventing crushing. The bottom ply and top liner ply then are transferred to a felt and carried through a press nip.

An object of the present invention is to provide an improved mechanism for forming linerboard at higher speeds than heretofore practical and forming improved linerboard with an improved ply bond between the layers.

A further object of the invention is to provide an improved device wherein the top liner ply is formed on the surface of the preformed lower ply and is dewatered between two wires carried over the arcuate surface of a breast roll.

A further object of the invention is to provide an improved more compact higher speed linerboard forming machine which avoids disadvantages of mechanisms heretofore available.

Other objects, advantages and features will become more apparent, as will equivalent structures which are intended to be covered, with the teaching of the principles of the present invention in the disclosure of the preferred embodiment in the specification, claims, and drawings, in which:

DRAWINGS DESCRIPTION As shown in the drawing, a bottom ply of linerboard is formed between first and second looped forming wires 10 and 11. The looped forming wires may be of metal wire or plastic fabric and are arranged to travel in runs by first and second guide means which include rolls that need not all be described in detail and are shown in their positions without all being numbered. Included in the guide rolls which form the first and second guide means is a breast roll 13 for the first wire and a couch roll 14. The second wire passes over a breast roll 15 and is turned over a couch roll 16. These rolls are so located so as to guide the first and second wires 10 and 11 into a forming throat 17 leading to a forming run 18 which preferably extends vertically upwardly.

Stock for forming the lower layer of the linerboard is delivered to the throat by a slice 9 positioned todeliver a spouting jet of stock into the throat. As the stock travels upwardly, it is dewatered by the pressure between the wires. Along the forming run within the first wire are skimmer blades 19 and 20 which deflect the water off of the wire surface and the water is caught by a saveall 21.

Within the second wire 11 along the forming run are a plurality of blades or edges 22 which deflect the wires laterally and which extend in a cross-machine direction, but are spaced apart in a machine direction so that the wires are threaded in a series of chords with the edges of the blades 22 generally positioned along an arc. Water which presses through the second wire flows along the blades 22 and is caught by a saveall 23.

Following the blades 22 is a suction box 24 which engages the wire.

The couch roll 16 is provided with a suction gland 25 having suction control means 25a so as to control the amount of water'removed from the web layer. In this manner the web .can be left sufficiently moist so as to insure a later transfer of water between the lower layer and the top linerply to insure a good bond between layers.

The couch roll 14 for the first wire wraps the first wire over the suction roll 16 to insure that the web will travel over the arcuate surface of the couch roll 16 and travel into the horizontal path 27 of the wire. Following this horizontal path, the second wire is wrapped over a No. 2 breast roll 28 within the second wire. This No. 2 breast roll is also wrapped by a third outer wire 30.

In advance of the nip formed between the third wire 30 and the second wire 11 is positioned a headbox 29 which delivers a stock to form the top liner ply over the lower ply carried on the wire 11. At this location the moisture in the lower ply is in the range of 6 to l2% and this moisture can be controlled quite well from the suction couch roll 16. The control of moisture is very important for a good ply bond between the top liner and bottom ply. The amount of stock needed for the top 3 liner is not very large, and the unit incorporated with the third looped wire 30 has sufficient drainage capacity to drain the water out of the top liner ply. As the top liner ply is laid on top of the bottom plybyt'he s'econdary headbox 29, the pressure between the third wire 30 and the second wire 11 forces water to be drained out and caught by a saveall 33. As the multi-ply web passes around the breast roll No. 2, 28 drainage continues to take place, and the multi-ply sheet is transferred from the second wire 11 to the third wire 30. This transfer is assisted by a suction roll 31 having a suction gland 32 therein. Control of the tension in the third wire 30 for controlling pressure against the layers is accomplished by a variable position roll 34 within the loop of the third wire 30.

Additional water coming off of the second top liner layer as it rounds the breast roll No. 2, 28 and the suction roll 31 is caught by a saveall 35.

To help consolidate the web and make a firmer bond therebetween, a preferred arrangement has a soft rubber cover over the breast roll 28. The hardness of this soft rubber is in the range of 50 P&J to 150 P&J

'Another feature is that the N; 3 wire 30 which can be either a wire or fabric is constructed to have large voids to permit a large amount of water to be carried by the fabric itself, and this helps avoid any crushing in the nip between the wires 11 and 30. The openness of the wire is in the range of 2.0 inf /ft. to 5.0 in. /ft.

The web is then transferred onto a first press felt 38. This is carried by suitable rolls within the looped felt including a suction transfer roll 36 having a suction gland 37 therein. The felt carrying the multi-layered web is then let down into the nip 39 formed between a press roll couple having an upper plain press roll 40 and a lower suction roll 41 with the suction gland 42 opposite the felt. The felt leaves the nip with the press and in a run 43, means are provided for lifting the web off the felt to a second press nip, not shown.

In the arrangement above described, the first forming run 18 forms a well formed sheet with dewatering being accomplished in both directions through the sheet and because the sheet is well formed, moisture can be retained without disadvantageous effects. The sheet is very flat and level and provides an improved linerboard grade. The arrangement requires relatively low driving power and provides ease of wire cleaning. A uniform high quality sheet results with ease of operation and low operating expense. With the top ply layer being dewatered outwardly, it is not necessary to draw water through the existing base ply which results in the requirement for less vacuum and less horsepower. With the use of a soft rubber covered breast roll 28, the advantages of a lump breaker roll are attained.

I claim:

1. A mechanism for making a multi-ply sheet from fibrous stock comprising in combination:

first and second looped forming wires;

first and second guide means within the respective wires training them to travel in a vertically extending forming throat leading to a vertically running forming run between the wires;

a first headbox having a slice positioned to discharge stock vertically into said throat to form a first web layer;

a suction couch roll within the second wire at the end of the forming run;

a breast roll within the second wire downstream from the forming run positioned horizontally of the couch'roll so that the second wire extends through a horizontal run to the breast roll and wraps the breast roll;

a third looped forming wire;

third guide means within the third wire training the third wire to wrap said breast roll over the second wire so that a multi-ply web on the second wire is dewatered outwardly through the third wire;

and a second headbox positioned in advance of said breast roll for directing a flow of stock horizontally onto the first web layer during said horizontal run tobe dewatered through said third wire over the breast roll.

2. A mechanism for making a multi-ply sheet from a fibrous stock constructed in accordance with claim 1: wherein said suction couch roll within the second wire at the end of the forming run has controlled suction means for controlling the moisture removed from the first web so that sufficient moisture remains for dewatering the first web in the direction of the second layer through the third wire.

3. A mechanism for making a multi-ply sheet from a fibrous stock constructed in accordance with claim 1: including a suction roll in the third wire following said breast roll training the third wire away from the second wire with the web following the third wire.

4. A mechanism for making a multi-ply sheet from a fibrous stock constructed in accordance with claim 3:

and including a felt receiving the web from the third wire and the press receiving the web and felt therein.

5. A mechanism for making a multi-ply sheet from a fibrous stock constructed in accordance with claim 1: including a felt removing the web from the third wire;

and a press receiving the web on the felt. 6. A mechanism for making a multi-ply sheet from a fibrous stock constructed in accordance with claim 1:

including a looped felt;

a suction roll within the felt forming a take-off nip with the third wire for removing the web therefrom;

and a press nip receiving the felt and web therebetween.

7. A mechanism for making a multi-ply sheet from a fibrous stock constructed in accordance with claim 6: wherein the press nip includes a plain roll engaging the web and a suction roll engaging the felt.

8. A mechanism for making a multi-ply sheet from a fibrous stock constructed in accordance with claim 1:

wherein said forming run extends vertically upwardly.

9. A mechanism for making a multi-ply sheet from a fibrous stock constructed in accordance with claim 1:

wherein said first forming run extends vertically upwardly in an arcuate path and said second guide means includes a suction couch roll over which the second wire is wrapped to turn into a generally horizontal run leading to said breast roll with means for controlling the tension of the third wire over said breast roll.

10. A mechanism for making a multi-ply sheet from a fibrous stock constructed in accordance with claim 1:

wherein the breast roll has a soft outer surface.

large voids. 13. A mechanism for making a multi-ply sheet from a fibrous stock constructed in accordance with claim wherein the voids in the wire have a size in the range of 2.0 in.''/ft, to 5.0 in. ft. 

1. A mechanism for making a multi-ply sheet from fibrous stock comprising in combination: first and second looped forming wires; first and second guide means within the respective wires training them to travel in a vertically extending forming throat leading to a vertically running forming run between the wires; a first headbox having a slice positioned to discharge stock vertically into said throat to form a first web layer; a suction couch roll within the second wire at the end of the forming run; a breast roll within the second wire downstream from the forming run positioned horizontally of the couch roll so that the second wire extends through a horizontal run to the breast roll and wraps the breast roll; a third looped forming wire; third guide means within the third wire training the third wire to wrap said breast roll over the second wIre so that a multiply web on the second wire is dewatered outwardly through the third wire; and a second headbox positioned in advance of said breast roll for directing a flow of stock horizontally onto the first web layer during said horizontal run to be dewatered through said third wire over the breast roll.
 2. A mechanism for making a multi-ply sheet from a fibrous stock constructed in accordance with claim 1: wherein said suction couch roll within the second wire at the end of the forming run has controlled suction means for controlling the moisture removed from the first web so that sufficient moisture remains for dewatering the first web in the direction of the second layer through the third wire.
 3. A mechanism for making a multi-ply sheet from a fibrous stock constructed in accordance with claim 1: including a suction roll in the third wire following said breast roll training the third wire away from the second wire with the web following the third wire.
 4. A mechanism for making a multi-ply sheet from a fibrous stock constructed in accordance with claim 3: and including a felt receiving the web from the third wire and the press receiving the web and felt therein.
 5. A mechanism for making a multi-ply sheet from a fibrous stock constructed in accordance with claim 1: including a felt removing the web from the third wire; and a press receiving the web on the felt.
 6. A mechanism for making a multi-ply sheet from a fibrous stock constructed in accordance with claim 1: including a looped felt; a suction roll within the felt forming a take-off nip with the third wire for removing the web therefrom; and a press nip receiving the felt and web therebetween.
 7. A mechanism for making a multi-ply sheet from a fibrous stock constructed in accordance with claim 6: wherein the press nip includes a plain roll engaging the web and a suction roll engaging the felt.
 8. A mechanism for making a multi-ply sheet from a fibrous stock constructed in accordance with claim 1: wherein said forming run extends vertically upwardly.
 9. A mechanism for making a multi-ply sheet from a fibrous stock constructed in accordance with claim 1: wherein said first forming run extends vertically upwardly in an arcuate path and said second guide means includes a suction couch roll over which the second wire is wrapped to turn into a generally horizontal run leading to said breast roll with means for controlling the tension of the third wire over said breast roll.
 10. A mechanism for making a multi-ply sheet from a fibrous stock constructed in accordance with claim 1: wherein the breast roll has a soft outer surface.
 11. A mechanism for making a multi-ply sheet from a fibrous stock constructed in accordance with claim 10: wherein the breast roll is rubber covered and has a hardness in the range of 50 P&J to 150 P&J.
 12. A mechanism for making a multi-ply sheet from a fibrous stock constructed in accordance with claim 1: wherein the third wire is an open type wire having large voids.
 13. A mechanism for making a multi-ply sheet from a fibrous stock constructed in accordance with claim 12: wherein the voids in the wire have a size in the range of 2.0 in.3/ft.2 to 5.0 in.3/ft.2. 